U.S. patent number 5,138,538 [Application Number 07/674,092] was granted by the patent office on 1992-08-11 for self-extinguishing flashlight.
Invention is credited to Michael Z. Sperling.
United States Patent |
5,138,538 |
Sperling |
August 11, 1992 |
**Please see images for:
( Certificate of Correction ) ** |
Self-extinguishing flashlight
Abstract
A flashlight having a self-extingushing feature that prevents
unintentional run-down of its batteries, particularly when used by
children, which is achieved by means of a circuit breaking device
controlled by a timer, and further having a bypass switch,
preferably of a child-proof nature, to override the
self-extinguishing feature and thereby improve the utility of such
flashlight as an ordinary household flashlight. Optionally, the
flalshlight may also have additional "child-proofing" mechanisms
such as an interlock to prevent unintended activation of the bypass
switch.
Inventors: |
Sperling; Michael Z. (Lawrence,
NY) |
Family
ID: |
24705260 |
Appl.
No.: |
07/674,092 |
Filed: |
March 25, 1991 |
Current U.S.
Class: |
362/205; 200/60;
315/360; 362/295; 362/394; 362/802 |
Current CPC
Class: |
F21L
4/00 (20130101); F21V 23/0414 (20130101); Y10S
362/802 (20130101) |
Current International
Class: |
F21V
23/04 (20060101); F21L 4/00 (20060101); F21L
007/00 () |
Field of
Search: |
;362/205,208,295,394,802
;446/485 ;315/74,76,360 ;200/60 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lazarus; Ira S.
Assistant Examiner: Quach; Y.
Attorney, Agent or Firm: Abramson; Ronald
Claims
I claim:
1. A self-extinguishing flashlight, comprising
a battery;
an on-off switch for controlling the flow of current from the
battery;
a timer means which changes state when a preset interval has
elapsed;
a circuit-breaking means connected in series with the on-off switch
and the battery having two controlled terminals and a control
input, wherein the control input is responsive to the state of the
timer means and electrical conductivity between two controlled
terminals is controlled by the aforementioned control input;
a light bulb in series with the on-off switch, the circuit breaking
means and the battery, so as to complete an electrical circuit when
the circuit breaking means and the on-off switch are in a
conductive state;
a bypass means connected in parallel across the controlled
terminals of the circuit breaking means; and
a hand-held housing having a base at one end, to accommodate and
position said battery, on-off switch, timer means, circuit-breaking
means, light bulb and bypass means such that the on-off switch is
accessible by hand and that light may be directed from the light
bulb away from the flashlight.
2. The self-extinguishing flashlight of claim 1, further comprising
an interlock means adapted such that switching off the on-off
switch also forces the bypass switch to an open position.
3. The self-extinguishing flashlight of claim 4, in which the timer
means is an electrically operated device.
4. The self-extinguishing flashlight of claim 3, in which the
on-off switch contains a separate pole for resetting the timer
means to a state representing zero elapsed time.
5. The self-extinguishing flashlight of claim 4, in which the
delayed action of the timer means is adjustable.
6. The self-extinguishing flashlight of claim 5, in which the
bypass means has been adapted to be child-proof, by means selected
from a group consisting of concealment in the base of the hand-held
housing, concealment elsewhere in the hand-held housing, or
restricting the movement of the bypass means with a device that
must be moved in order to activate the bypass means, which device
requires particular muscle coordination and strength in order to be
moved.
7. The self-extinguishing flashlight of claim 3, in which the
delayed action of the timer means is adjustable.
8. The apparatus of claim 7, in which the bypass means has been
adapted to be child-proof, by means selected from a group
consisting of concealment in the base of the hand-held housing,
concealment elsewhere in the hand-held housing, or restricting the
movement of the bypass means with a device that must be moved in
order to activate the bypass means, which device requires
particular muscle, coordination and strength in order to be
moved.
9. The self-extinguishing flashlight of claim 2, in which the
delayed action of the timer means is adjustable.
10. The apparatus of claim 4, in which the bypass means has been
adapted to be child-proof, by means selected from a group
consisting of concealment in the base of the hand-held housing,
concealment elsewhere in the hand-held housing, or restricting the
movement of the bypass means with a device that must be moved in
order to activate the bypass means, which device requires
particular muscle coordination and strength in order to be
moved.
11. The self-extinguishing flashlight of claim 1, in which the
timer means is an electrically operated device.
12. The self-extinguishing flashlight of claim 11, in which the
on-off switch contains a separate pole for resetting the timer
means to a state representing zero elapsed time.
13. The self-extinguishing flashlight of claim 1, in which the
delayed action of the timer means is adjustable.
14. The self-extinguishing flashlight of claim 1, in which the
bypass means has been adapted to be child-proof, by means selected
from a group consisting of concealment in the base of the hand-held
housing, concealment elsewhere in the hand-held housing, or
restricting the movement of the bypass means with a device that
must be moved in order to activate the bypass means, which device
requires particular muscle coordination and strength in order to be
moved.
15. A self-extinguishing flashlight, comprising
a hand-held housing having a base at one end;
a battery;
an on-off switch positioned in the housing so as to be accessible
by hand, for controlling the flow of current from the battery;
a timer means which changes state when a preset interval has
elapsed;
a circuit-breaking means connected in series with the on-off switch
and the battery having a control input responsive to the state of
the timer means;
a light bulb in series with the on-off switch, the circuit breaking
means and the battery, and positioned in the housing so as to
direct light away therefrom; and
a bypass switch connected directly from the battery to the light
bulb, which bypass switch has been adapted to be child-proof, by
means selected from a group consisting of concealment in the base
of the hand-held housing, concealment elsewhere in the hand-held
housing, or restricting the movement of the bypass switch with a
device that must be moved in order to activate the bypass switch,
which device requires particular muscle coordination and strength
in order to be moved.
Description
BACKGROUND OF THE INVENTION
This invention relates to hand-held light sources, and more
particularly to flashlights having means to turn themselves off
after a predetermined interval, particularly when used by children.
It further relates to the incorporation in general purpose
household flashlights of bypass and "child-proofing" mechanisms
such that if such flashlights are played with by children their
batteries will not be completely drained, but will retain power for
service in emergencies. Furthermore, the bypass mechanism can be
used to ensure that the flashlight will not turn itself off during
an emergency or other situation in which uninterrupted service is
desired.
Hand-held light sources have been used in one form or another for
millennia. Ancient legend recounts Diogenes' fruitless search for
an honest man as having been conducted with the unaviling aid of a
hand-lantern. Prehistoric light sources were doubtless torches, but
the invention of the oil lamp made possible the hand-lantern, its
wick sheltered in a wind-proof housing. At a later stage, candles
supplanted the oil lamp, only themselves to yield to kerosene lamps
in the late 19th century. Carbide lamps, in turn, supplanted those
in such applications as mining, until modern times, when the
perfection of durable dry cells made what the English call the
electric torch, and what is known in America as the flashlight, a
practical alternative.
Until the invention of the flashlight, all hand-lanterns employed a
flame and a reservoir of flammable material, whether liquid or
solid. Such lanterns were capable of igniting a conflagration in
the home, the barn or the workplace, and were therefore reserved
exclusively for use by adults, since no child could be trusted to
handle one safely. However, the advent of the flashlight eliminated
that danger, and while flashlights retain their essential role of
safe and convenient portable light sources, they have become widely
available to children as toys.
No parent will permit a child to play with matches or candles, but
most will indulgently permit their children to use their bedsheets
as a tent, and to pretend to "camp out" on their beds, reading
their favorite book by the light of a flashlight. Of course, the
children are soon fast asleep, but when parents tiptoe in to tuck
them in for the night, the flashlight buried in the bedclothes is
often forgotten, and by morning its batteries are fully
discharged.
Similarly, when children are sent off to summer camp with the
obligatory flashlight, its batteries are typically discharged
during the first evening hike or campfire entertainment. All
children are adept at switching on a flashlight, but none seems
capable of switching one off.
Since most modern batteries are leakproof and will not ruin a
flashlight by leaking when fully discharged, it might be imagined
that the cost of replacing batteries is the only consequence of
such unintended discharge. However, the more serious problem is the
fact that in a household with children even flashlights reserved
for emergency use are subject to the same fate. A flashlight is as
irresistible to a child as the proverbial flame is to a moth. Every
flashlight within reach is used as a toy, and no shelf is high
enough, nor any hiding place secret enough to keep a flashlight
from a child's reach. When, in an emergency, a parent tries to
switch one on, its failure to respond with even a dim glow
testifies to the child's diligence in searching out the
irresistible plaything.
As noted earlier, the central problem is to get the flashlight
swithched off. A child's attention span is short, so the play
centered on the flashlight is soon replaced by another game or
interest, while the flashlight is abandoned to discharge its
batteries unnoticed.
Ordinary flashlights have addressed some of these concerns in a
limited manner by often including a button that can be pressed in
lieu of turning on the main power switch in order to turn the light
on momentarily. Primarily, this added element was intended to
permit on-off or Morse-code signaling or flashing--an early feature
that gave rise to the appellation "flashlight"--rather than as a
means to conserve batteries. Other, small, flashlights have been
sold which included switches whose contacts are closed when the
barrel of the flashlight is squeezed. None of such mechanisms, of
course, will by themselves keep the flashlight lit after they are
let go of, and hence their utility for the purposes discussed
herein is limited.
Various methods of providing a flashlight with a delayed means of
deactivation are also known in the art. These address more directly
the concerns noted above, although each such prior art device has
distinct disadvantages. Mallory, in U.S. Pat. No. 3,535,282,
disclosed a flashlight in which means, such as a spring and bellows
arrangement utilizing a controlled air leak to control
decompression of the spring, were employed to open the power switch
in a flashlight after a predetermined interval. Auer, in U.S. Pat.
No. 4,875,147 disclosed a flashlight that employed a suction cup as
a delayed action element to control the release of a power switch.
An electronic means for obtaining a delayed action is employed in
toy flashlights sold by Playskool, Inc. and by Fisher-Price Toys.
The Playskool flashlight uses a resistor-capacitor timing circuit
to apply a bias to a solid-state switching element in order to shut
off the flashlight after about a 30-second interval following a
child's release of a handle containing a spring-loaded on-off
switch. The Fisher-Price flashlight uses an electronic timing
circuit simply to turn off the flashlight after about 20
minutes.
It is observed that the above-mentioned delayed-action prior art
devices provide no means for overriding the self-extinguishing
mechanism in order to enable unattended use for extended periods
when so desired. In the ordinary household use of a flashlight it
is sometimes necessary to be able to have the light remain on for
an extended period without having to hold or keep reactivating the
flashlight. The absence of such a capability prevents such prior
art devices from fully meeting the requirements of a
general-purpose household flashlight.
In addition, the devices disclosed by Auer and Mallory operate by
turning off the main power switch itself, which tends to limit the
available delayed action devices to bulky and relatively
complicated mechanical structures. Furthermore, the device sold by
Playskool employs a solid-state switch which entails a drop of
approximately one-half volt across a semiconductor junction,
noticeably reducing the brightness of the flashlight.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a more simple
and effective means than those known in the art for switching off a
flashlight after a preset interval has elapsed, in order to prevent
unintentional discharge of its batteries, particularly when used by
children. A further object is to provide a convenient means of
overriding the automatic switch-off function, when lengthy,
uninterrupted service is desired. It is yet a further object of the
invention to provide the foregoing functions in a manner such that
the desired operational characteristics cannot easily be evaded by
children. Other objects and advantages of the invention will become
apparent upon reference to the figures.
Briefly stated, these objects are attained in a flashlight having
the usual components of a battery, an on-off switch, a bulb and a
hand-held housing, to which there is added a timing means and a
circuit-breaking means responsive to the timing means for cutting
off the flow of current to the bulb, and which further has a bypass
means, preferably child-proof, to direct electric current to the
light bulb regardless of the state of the timing means. The
operation of such device may be further enhanced by making the
bypass means a switch connected so as to leave it in series with
the on-off switch. Furthermore, an interlock or other
"child-proofing" mechanism may be provided to ensure that the
bypass is disabled when the flashlight is switched off.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a shows a functional schematic diagram of an ordinary
flashlight.
FIG. 1b shows a functional schematic diagram in which a flashlight
incorporates a timer circuit, and in which a bypass switch is in
parallel with and serves to bypass both the flashlight's on-off
switch and the timer circuit.
FIG. 2 shows an embodiment in which the bypass switch is in
parallel with the timer circuit, but in series with the on-off
switch.
FIG. 3 shows an alternative embodiment based on that of FIG. 2, but
in which an interlock arrangement is added between the on-off
switch and the bypass switch.
FIG. 4 shows a flashlight contained in a housing and constructed in
accordance with the circuit of either FIG. 1b or FIG. 2, on which
can be seen the on-off switch (4) and the light bulb (3) of FIGS.
1b and 2, and a means (10) of restricting the movement of the
bypass switch (4) of FIGS. 1b and 2. (The bypass switch itself is
not visible in FIG. 4 because it is situated under the movement
restricting means).
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a form of flashlight that augments the
ordinary flashlight, depicted schematically in FIG. 1a, with
additional functionality. The present invention is readily
understood upon reference to FIG. 1b, which shows one embodiment of
the present invention. That embodiment, comprises an ordinary
flashlight to which have been added a timer, a circuit-breaking
device and a bypass switch. An ordinary flashlight, as shown in
FIG. 1a, comprises a battery of dry cells (2) connected to a light
bulb (3) through an on-off switch (4). As mentioned above, such
flashlights often include an additional switch, not shown here,
which is a contact switch in parallel with the on-off switch, that
is provided for flashing or signalling by momentarily turning on
and off the electric current.
Note in FIG. 1b the addition of a timer (5) to control a
circuit-breaking device (6), to automatically disconnect the light
bulb from the circuit after a preset interval. Note that a bypass
switch (7) provides an alternative path for current to the light
bulb, and thus can be used to override the automatic switching off
function. Bypass switch (7) would typically be used by an adult who
wanted to prevent interruption of the light by the time switching
off function, and would preferably be "child-proofed." Such
child-proofing might be attained by concealing bypass switch (7) in
the flashlight base (9) or elsewhere in the flashlight, or by
leaving it in plain sight but restricting its movement by
inexpensive means (10) requiring particular muscle coordination and
strength in order to be operated, such as the closure of a medicine
container (10).
In ordinary operation, closing the on-off switch does two things:
it resets timer (5) to zero and restarts it; and it powers circuit
breaker (6), closing it to complete the circuit from battery (2) to
light bulb (3). The timer may comprise any number of devices,
including a digital clock, a resistor-capacitor timer, etc.
Circuit-breaker (6), here illustratively shown as
electromechanical, may also be one of several types of devices,
including a solid-state switch. While an electromechanical device
may draw a significant percentage of the battery's load, it can
easily switch current to the light bulb, that can be on the order
of one ampere, without imposing the forward voltage drop of a
suitable solid-state device, typically one-half volt. When the
predetermined timer interval has elapsed, timer (5) switches open
circuit-breaker device (6), switching off the light and removing
from the battery the additional load of circuit-breaker device (6).
At this point, the only load on the battery is the negligible one
comprised of the high-impedance input to the timer (5). That load
can be designed to draw less current than the internal,
self-discharge leakage current of the battery, and may therefore be
ignored.
To relight the flashlight, battery (2) is briefly disconnected from
timer (5) to reset the timer, and battery (2) is then reconnected
to start the timing cycle again and to close circuit-breaker (6).
This can be accomplished by switching the on-off switch (4) first
off and then promptly on again. If the timer is based on the
charging rate of a capacitor, for example in a resistor-capacitor
charging circuit, it may be most convenient to discharge the
capacitor through an additional pole on the on-off switch.
Note that in this embodiment bypass switch (7) bypasses both the
timer (5) and the on-off switch (4). A clever child who might
manage to operate bypass switch (7) might also notice that when
that switch was used instead of the on-off switch, the flashlight
would remain lit, rather than going off after a while. That
awareness might lead such a child to use the bypass switch in
preference to the on-off switch, vitiating the intended function of
the timer.
This possibility is prevented by the embodiment of FIG. 2, in which
bypass switch (7) only bypasses the timer and the circuit-breaker
it controls. Therefore, if a child should manage to switch on the
bypass switch, the flashlight will not light unless the on-off
switch is also switched on. Similarly, if the child should manage
to switch off the bypass switch while the flashlight is lit, he
will find that it has no effect, since the light will remain on.
The child who experiments with these two switches will conclude
that the bypass switch has no effect on the light, and will ignore
that switch in the future, assuring the timer function the proper
control of the flashlight. In all other respects, this embodiment
would function like that of FIG. 1b.
FIG. 3 illustrates a variant of the arrangement shown in FIG. 2.
Here, an interlock (8) is added to link on-off switch (4) and
bypass switch (7), so bypass switch (7) cannot inadvertently be
left in its closed position when the flashlight is switched on
after use. When the on-off switch (4) is switched off, interlock
(8) also switches bypass switch (7) to an open position. This is
the only situation in which the interlock has an effect. Thus, when
the flashlight is next switched on, bypass switch (7) must be
deliberately switched on, if so desired, and cannot simply be left
on from its last use.
The embodiments described above clearly realize the stated objects
of the invention, yet are not intended as an exhaustive compilation
of the invention's content of patentable novelty. Numerous further
variants will be obvious and may be effected by anyone skilled in
the art without departing from the scope or spirit of the
invention. For example: the timer may be a mechanical device such
as a dashpot and spring arrangement; the timer interval may be made
adjustable, either through analog or digital means, to match the
attention spans of younger or older children; to aid in resetting
the timer, the on-off switch may be of the double-pole,
single-throw (DPST) variety, rather than the single-pole,
single-throw type shown in the figures, etc.
* * * * *